Method for reducing noise in digital images

Abstract

A method for cleaning the noise in an image obtains an image having an interested pixel and a predetermined number of neighboring pixels for each of red, green and blue, then calculates an adjusted value for the interested pixel based on the existing value of the interested pixel and the values of the predetermined number of neighboring pixels. This calculation is carried out for each of red, green and blue using the same predetermined number of neighboring pixels.

1 . A method for cleaning the noise in an image, comprising: 
 a. obtaining an image having an interested pixel and a predetermined number of neighboring pixels;    b. defining a threshold;    c. obtaining the difference between the value of each neighboring pixel and the value of the interested pixel;    d. classifying each of the neighboring pixels as being larger than the threshold (LTT) or smaller than the threshold (STT) based on the differences calculated in step (c);    e. replacing the value of the LTT pixels with the value of the interested pixel, while retaining the values of the STT pixels;    f. calculating the average value of all the predetermined number of pixels obtained from step (e) and the interested pixel; and    g. replacing the original value of the interested pixel with the average value.    
   
   
       2 . The method of  claim 1 , wherein steps (a)-(g) are performed for each of red, green and blue colors.  
   
   
       3 . The method of  claim 2 , wherein the predetermined number of neighboring pixels is the same for red, green and blue.  
   
   
       4 . The method of  claim 2 , wherein the predetermined number of neighboring pixels is nine for red, green and blue.  
   
   
       5 . The method of  claim 1 , wherein the predetermined number of neighboring pixels is nine for green.  
   
   
       6 . A method for cleaning the noise in an image: 
 a. obtaining an image having an interested pixel and a predetermined number of neighboring pixels for each of red, green and blue;    b. calculating an adjusted value for the interested pixel based on the existing value of the interested pixel and the values of the predetermined number of neighboring pixels; and    c. repeating step (b) for each of red, green and blue using the same predetermined number of neighboring pixels.